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1.
The latent potential for problematic weed growth in a hydro-lake is proportional to water level fluctuation, water clarity, lake shape, littoral gradient and exposure to wave action. These five factors were used to assess a score for measuring the latent potential for weed impact and each factor was allocated a score of 1–5, with a theoretical maximum of 25. Any hydro-lake scoring above 15 could be expected to present potential inconvenience to power generation, given the presence of suitable submerged weed species. Assessment of potential impact arising from weed invasion must firstly determine what species are already established, and whether it is possible for a weed species of greater potential impact to be introduced. The risk of this occurring is dependent upon a number of factors, including public accessibility, proximity to sources of those species and the desirability of the waterbody to potential weed vectors. Once these factors are quantified, appropriate surveillance strategies in high-risk hydro-lakes may then be developed.  相似文献   

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广州外来入侵植物   总被引:6,自引:4,他引:6  
根据野外调查及相关文献资料,初步探讨了广州市外来入侵植物的种类组成、分布生境、生长特性、危害以及来源.结果表明:广州市现有外来人侵植物73种,隶属于27科59属,其中菊科(19种)、禾本科(8种)、豆科(7种)和苋科(7种)植物占了入侵植物总种数的56.2%.生活型分析发现,在广州有分布的外来入侵植物中,陆生草本植物最多(58种),其次为灌木(10种)、水生草本(3种),乔木种类最少(2种),它们主要生长在人类干扰比较频繁的低海拔地区.另外,基于对外来入侵植物目前在野外的生长和分布状况等生态学特性进行分析,可大致将它们对本地生物多样性危害程度分为3级,其中危害严重的有11种,危害中等的有25种,危害较轻的有37种.从原产地分析来看,61种来自于热带美洲地区,占广州外来入侵植物总种数的83.6%.与国内其他地区外来入侵植物进行比较发现,广州和广西共有种数最多,有62种,然而,对已经造成严重危害的外来植物种类,在数量上广州与香港、深圳和广西相同种类较多,分别有8种、7种和6种.对广州市目前外来植物的入侵风险(潜在威胁)的评估结果表明,对一些在其它地区已经造成严重危害的外来植物,应当加强监控,防止入侵扩散并造成重大生态灾难.还对广州市外来植物入侵的主要途径及防治策略做了简要分析和说明.  相似文献   

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  总被引:2,自引:1,他引:1  
To assess the validity of previously developed risk assessment schemes in the conditions of Central Europe, we tested (1) Australian weed risk assessment scheme (WRA; Pheloung et al . 1999); (2) WRA with additional analysis by Daehler et al . (2004); and (3) decision tree scheme of Reichard and Hamilton (1997) developed in North America, on a data set of 180 alien woody species commonly planted in the Czech Republic. This list included 17 invasive species, 9 naturalized but non-invasive, 31 casual aliens, and 123 species not reported to escape from cultivation. The WRA model with additional analysis provided best results, rejecting 100% of invasive species, accepting 83.8% of non-invasive, and recommending further 13.0% for additional analysis. Overall accuracy of the WRA model with additional analysis was 85.5%, higher than that of the basic WRA scheme (67.9%) and the Reichard–Hamilton model (61.6%). Only the Reichard–Hamilton scheme accepted some invaders. The probability that an accepted species will become an invader was zero for both WRA models and 3.2% for the Reichard–Hamilton model. The probability that a rejected species would have been an invader was 77.3% for both WRA models and 24.0% for the Reichard–Hamilton model. It is concluded that the WRA model, especially with additional analysis, appears to be a promising template for building a widely applicable system for screening out invasive plant introductions.  相似文献   

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外来入侵物种的风险评估定量模型及应用   总被引:10,自引:0,他引:10  
预防生物入侵的一个重要手段是对外来物种进行风险评估,应用模型则是定量评估的必备方法。本文简述了常用的适生性风险评估模型,概述了诸如遗传算法、模糊包络模型、自组织特征映射网络等较新的理论方法,它们使用环境变量和物种实际分布数据,利用不同的机理模型预测物种潜在分布区。本文还综述了适用于研究物种扩散性的模型,积分差分方程模型可以模拟物种扩散行为,元胞自动机模型可以揭示种间竞争关系,景观中性模型大多用于种群动态等生态过程的研究。  相似文献   

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《重点管理外来入侵物种名录》(简称《重点名录2023》)于2023年1月1日起正式施行,该名录对我国外来入侵物种防控管理具有重要的指导作用。本文梳理了我国外来入侵物种名录修订背景及概况,比较了《重点名录2023》和其他名录中外来入侵植物物种的差异,并分析了《重点名录2023》中33种外来入侵植物的危害性和扩散程度。《重点名录2023》与4批“中国外来入侵物种名单”和《国家重点管理外来入侵物种名录(第一批)》中的植物物种重合度较高。33种外来入侵植物对我国生态、农业、林业、人畜健康均有严重危害,且扩散范围广,但仍有值得商榷的问题。本文详述了《重点名录2023》在分类争议和前期评估上存在的问题和缺口,并对我国外来入侵植物物种名录的动态调整和分类管理提出了思考和建议。  相似文献   

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  总被引:1,自引:0,他引:1  
Roadside plant communities were studied along two roads following an altitudinal gradient in Gran Canaria and Tenerife (Canary Islands). Our aim was to investigate variation in plant species richness, particularly of the alien flora, along a gradient from coastal shrubland to summit vegetation (1950 m a.s.l. in Gran Canaria, 2300 m in Tenerife) in relation to variation in habitat factors (altitude, habitat structure, roadside disturbance, distance to urban nuclei). We compared different species groups that were classified in terms of their biogeographical status, origin and life form. Altitude was the most important factor determining species richness and composition along both roadside transects. Alien plants showed a unimodal distribution pattern along the altitudinal gradient, with less species and lower abundance at low and high altitudes, and highest abundance at intermediate altitude. Alien plant species were also relatively more frequent near urban centres. The number of native and alien species was significantly positively correlated along the altitudinal gradient. Both alien and native, non-endemic species showed differences in their distribution along the altitudinal gradient according to their biogeographical affinities and climatic tolerances. Despite considerable differences in species pools these patterns were consistent among the two islands. Environmental (abiotic) stress is proposed as a primary, altitude-related factor acting as a filter against most alien plants at coastal and high-mountain altitudes. A higher frequency or intensity of disturbance at intermediate altitudes may be a further causal factor promoting alien plants in this zone. Future management efforts to control alien plants along roads should, therefore, concentrate on intermediate altitudinal zones of the higher Canary Islands.  相似文献   

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基于中国外来入侵植物的相关报道与文献,发现一些入侵植物的学名使用比较混乱:不同时期、不同地区、不同作者在报道同一外来物种时使用不同的学名,或因中文名相近,而将其他植物作为外来入侵植物报道。依据最新资料,对国内报道的16种外来入侵植物学名进行了考证,包括中文名、英文名、异名、原产地及其在国内外的分布情况。  相似文献   

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Crupina vulgaris (common crupina) is an invasive annual plant of rangelands and pastures in the United States (USA). There are two varieties of C. vulgaris in the USA that differ morphologically and biologically, particularly in requirements for bolting. A vernalization protocol enabled synchronization of bolting, thus facilitating concurrent comparative studies of both varieties. Leaf-removal experiments suggest that all leaves provide photosynthate for seed fill, but the cauline leaves, on a relative basis, produced 1.7–4 times more seed per g than rosette leaves, suggesting disease on the cauline leaves has greater potential to reduce seed production than disease on rosette leaves. Ramularia crupinae, a leaf-spotting fungus, was evaluated for biological control. A single inoculation caused a 47% reduction in root dry weight, and seed yield was reduced by 39% as the number of inoculations increased from 0 (controls) to 3. None of 35 non-target taxa, i.e., species, cultivars, and varieties, in the tribe Cardueae was damaged from inoculation by R. crupinae, including safflower, which developed a few, small necrotic spots on old leaves. Best Linear Unbiased Predictors (BLUPs), generated by a mixed model analysis of disease reaction and genetic relatedness data, indicated that only C. vulgaris varieties were susceptible to disease; i.e., BLUPs were significantly different from zero (p > |t| < 0.05). None of the other taxa had BLUP estimators that were significantly different from zero and were, therefore, determined to be not susceptible to disease by R. crupinae. Results suggest that R. crupinae is a potentially good candidate for biological control of this important weed pest and would likely not affect other species of importance in the USA.  相似文献   

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Aim Biological invasions pose a major conservation threat and are occurring at an unprecedented rate. Disproportionate levels of invasion across the landscape indicate that propagule pressure and ecosystem characteristics can mediate invasion success. However, most invasion predictions relate to species’ characteristics (invasiveness) and habitat requirements. Given myriad invaders and the inability to generalize from single‐species studies, more general predictions about invasion are required. We present a simple new method for characterizing and predicting landscape susceptibility to invasion that is not species‐specific. Location Corangamite catchment (13,340 km2), south‐east Australia. Methods Using spatially referenced data on the locations of non‐native plant species, we modelled their expected proportional cover as a function of a site’s environmental conditions and geographic location. Models were built as boosted regression trees (BRTs). Results On average, the BRTs explained 38% of variation in occupancy and abundance of all exotic species and exotic forbs. Variables indicating propagule pressure, human impacts, abiotic and community characteristics were rated as the top four most influential variables in each model. Presumably reflecting higher propagule pressure and resource availability, invasion was highest near edges of vegetation fragments and areas of human activity. Sites with high vegetation cover had higher probability of occupancy but lower proportional cover of invaders, the latter trend suggesting a form of biotic resistance. Invasion patterns varied little in time despite the data spanning 34 years. Main conclusions To our knowledge, this is the first multispecies model based on occupancy and abundance data used to predict invasion risk at the landscape scale. Our approach is flexible and can be applied in different biomes, at multiple scales and for different taxonomic groups. Quantifying general patterns and processes of plant invasion will increase understanding of invasion and community ecology. Predicting invasion risk enables spatial prioritization of weed surveillance and control.  相似文献   

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Compilation of alien flora from phytogeographically distinct regions is of immediate relevance not only for better understanding the patterns of plant invasion but also for explicating the processes promoting invasion at local, regional or global scales. Despite being at higher risk of invasion by plants because of its European colonial past, south Asia has received very little attention in respect of characterization of its alien flora. This paucity of baseline data necessitated compilation of the first catalogue of alien flora from the Kashmir Himalaya—a phytogeographically distinct south Asian region nestled in the northwestern folds of Himalayan biodiversity hotspot. Total alien flora of the region is represented by 571 plant species, belonging to 352 genera and 104 families. It constitutes a relatively higher (29%) proportion of the total flora of the region. Families with largest number of alien representatives are Poaceae (60 species), Asteraceae (54 species), and Brassicaceae (30 species). However, families such as Amaranthaceae (83%) and Chenopodiacae (71%) show higher percentage of aliens relative to their total number of plant species in the region. Most of the alien plant species (38%) trace their origin to Europe, followed by Asia (27%) and Africa (15%). Present study also reports, for the first time, occurrence of seven plant species in this region. Each alien plant species is provided with information on the origin, habit, mode/purpose of introduction, current invasion status, altitudinal range and the primary published source.  相似文献   

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Invasive alien plants in China: diversity and ecological insights   总被引:4,自引:0,他引:4  
China’s current invasive alien plant species were analyzed with regard to their floristic status, biological attributes and invasion status elsewhere. Most of the 270 species identified were annuals, followed by perennial herbs. Woody perennials made only about 10% of the species. The invasives were comprised of 59 families, the largest being Asteraceae, Poaceae, and Brassicaceae. The genera with most invasive species were Amaranthus, Ipomoea, and Solanum. Most of the species originated from the New World, notably from South America. About one-third of the species were serious invaders of natural habitats in countries other than China. The proportion of invasive alien plants in province floras ranged from 0.5 to 3.8%, absolute numbers from nine to 117 species per province. Density of invasive species was correlated positively with native species density at provincial scale. The results demonstrate that in China invasive plants are present throughout the country, with a particularly high species richness in the Southeast. The ecological diversity of invasive plants suggests wide ranging impacts which need to be assessed.  相似文献   

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浙江省外来入侵植物研究   总被引:16,自引:0,他引:16  
基于国内外文献资料、标本信息和野外调查,初步整理了浙江省外来入侵植物的种类组成、生活型、原产地、危害程度和入侵途径。结果表明,浙江省现有外来人侵植物46科106属166种,种数最多的是菊科、豆科和禾本科。根据原产地分析,来源于南美洲的物种最多,约占总数的32.16%,其次为北美洲,约占总数的25.63%,欧洲排第三位,约占总数的19.59%;已产生严重危害的有23种,中等危害的60种,危害较轻的83种。还有一些物种虽然没有在表里列出,但它们具有潜在的危害,必须密切关注。同时,与之前的研究相比,我们去除了一些已报道为人侵的物种,又增加了一些新的入侵种。在此基础上,对浙江省外来入侵植物的生活型、来源及危害进行了分析,并与以往的研究进行了比较,提出了针对性的管理建议。  相似文献   

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上海外来植物及其入侵等级划分   总被引:1,自引:0,他引:1  
汇总分析了上海外来植物75科232属357种(和种下类群)基础资料,并对其入侵危害进行等级划分;其中入侵植物64种,一般或偶见外来植物293种;报道了9种上海新纪录逸生植物。上海外来植物总体呈现种类繁多、国产种类较多、分布密度大、严重危害种类较多且分布广、入侵途径集中等特征。同时对上海外来入侵植物的管理与防治提出具体措施。  相似文献   

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浙江省外来入侵植物研究   总被引:1,自引:0,他引:1  
基于国内外文献资料、标本信息和野外调查,初步整理了浙江省外来入侵植物的种类组成、生活型、原产地、危害程度和入侵途径。结果表明,浙江省现有外来入侵植物46科106属166种,种数最多的是菊科、豆科和禾本科。根据原产地分析,来源于南美洲的物种最多,约占总数的3216%,其次为北美洲,约占总数的2563%,欧洲排第三位,约占总数的1959%;已产生严重危害的有23种,中等危害的60种,危害较轻的83种。还有一些物种虽然没有在表里列出,但它们具有潜在的危害,必须密切关注。同时,与之前的研究相比,我们去除了一些已报道为入侵的物种,又增加了一些新的入侵种。在此基础上,对浙江省外来入侵植物的生活型、来源及危害进行了分析,并与以往的研究进行了比较,提出了针对性的管理建议。  相似文献   

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An analysis of relevant literature and specimen records was conducted, together with field investigations, to examine the species composition, life form, origin, harmfulness and form of introduction of alien invasive plants in Zhejiang Province, China. A total of 166 alien invasive plant species belonging to 106 genera and 46 families were identified. The most common families represented were Asteraceae, Leguminosae and Gramineae, while the most common places of origin were South America, accounting for 3216% of all species, followed by North America (2563%) and Europe (1959%). Twenty three of the species were considered to cause high levels of damage, 60 medium levels of damage, and 83 low or minimal damage. Based on our records, we removed some invasive species from existing lists and added some new ones. Several suggestions for the management of invasive plants in Zhejiang Province are presented.  相似文献   

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报道中国外来入侵植物的文献众多,然而不少物种的学名使用混乱。不同时期、不同地区的不同作者在报道同一物种时,使用不同的学名,或因中文名相近,将其他物种作为外来入侵植物报道,从而给入侵植物的研究造成混乱。依据最新植物志等权威资料,对国内文献报道的20种入侵植物的学名进行了考证,包括中名、异名,原产地及其在国内外的扩散情况以及必要的讨论等。  相似文献   

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Brazilian peppertree, Schinus terebinthifolia Raddi (Anacardiaceae), was introduced into Florida, USA, from South America as an ornamental plant in the late 19th and early 20th centuries. It eventually escaped cultivation and is a serious threat to the state’s biodiversity. In the 1980s, this invasive weed was targeted for classical biocontrol. Surveys for natural enemies of Brazilian peppertree conducted in the native range resulted in the discovery of several candidate biocontrol agents. A stem-boring weevil identified as Apocnemidophorus pipitzi (Faust) was collected in Paraguay and transported under permit to Florida, USA. A laboratory colony of A. pipitzi was established in April 2007 by caging adults on cut branches of Brazilian peppertree supplemented with leaf bouquets. Adults are defoliators that feed mainly on the upper surface of subterminal leaflets. Females deposit eggs singly inside the stems and larvae feed under the bark where they damage the vascular cambium. There are five instars, pupation occurs inside the stem and a new generation is produced in 3–4 months. Growth of potted plants with and without exposure to weevil herbivory was compared over an 11-month period. Feeding damage by adults and larvae significantly increased leaf abscission and reduced leaf and root biomass accumulation.  相似文献   

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